


Treacherous Desires

by RHoldhous



Category: Fate/stay night & Related Fandoms
Genre: Anal Sex, F/F, Face-Fucking, Futa on Female, Futanari, Other, Smut, f/f - Freeform
Language: English
Status: Completed
Published: 2018-03-30
Updated: 2018-03-30
Packaged: 2019-04-14 23:30:17
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 3,173
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/14146995
Author URL: https://archiveofourown.org/users/RHoldhous/pseuds/RHoldhous
Summary: Mordred cannot resist her step-father's advances, and must therefore bear the full force of her magnificent "weapon".





	Treacherous Desires

**Author's Note:**

> Note: This story is a work of fiction. It has many content of adult nature. If you do not want to read such content, please close your browser window or press the convenient back button.

She was not sure how admiration had become attraction, a perverted sort at that. She didn't know and she didn't care to know. The only thing on her mind now was the message she'd received, from the King.

"Come to my room after supper."

A short statement, nothing more, nothing less. She could not for the life of her guess the King's purpose for summoning her? A rebuke? A private meeting? For as long as she knew her step-father, she had seen them to be a distant figure: stoic and authoritative, distant and powerful, like a graven statue carved from the bones of a mountain.

"My King?" she said, knocking on the door.

"Enter," was the reply, short and to the point.

Mordred steeled herself. She shook her head, frustrated to feel like she were a maiden on some loathsome rendezvous. No, she was not that weak, even if she was going into the lion's own den. She was a lion herself, damn it!

She stepped into the room. She raised her hand in salute-then her breath hitched up when she beheld perfection.

It was never clear beneath all that armor, but her step-father Artoria was quite voluptuous once everything had been taken off. Now, clad in modest silk robes that barely attempted to conceal her skin, she didn't quite look like the seasoned warrior. And yet, sitting there on her chair, the King's regal presence was not diminished-in fact, under the dim glow of the room she seemed to glow with some innate magical splendor that near blinded her. Her long, curvy, powerful legs draped against each other, bared, as she nursed a goblet in her hand. Her golden hair, free of the crown's burden, was still nonetheless bound in the same bun, and she twirled a stray lock around her finger; her green eyes smouldered with an emotion that she couldn't quite understand, but it felt so raw and intimidating, like a predator sizing up a meal.

Without even being conscious about it, Mordred felt herself seize up, especially when the King set aside the goblet and rose to her feet without saying a word. As the King loomed above her, making her more and more aware of the differences in their size, Mordred felt a strong desire to run away. But she could not, mesmerized as she was by those eyes.

"P-pardon me," she stammered, her throat dry. "But was there something...?"

"Did you think I would not notice?" Artoria said, her sleek mask of her face shifting into a slight bemusement. She shifted, and Mordred saw her silk garments slide over her body, at once exposing and masking the beautiful skin and the curves of her body tantalizingly.  _Damn it, pull yourself together!_  she shouted in her mind, wrenching her eyes away from the sight.

"I think it is quite the time to stop lying to ourselves," the King continued, taking yet another step forward, until Mordred could practically feel the warmth of her body. Mordred was breathing hard and fast now, though she did not yield an inch backward and stood her ground. "You want something from me, don't you? I've known of your ambitions for a long time." the King asked. "As it happens, I am perfectly willing to give it to you."

"Wh-what is-"  _Oh god, her face is so close!_

"Shush now," Artoria said, her voice whispering close to her ear, though with how much she was clenching she could not see how close. Mordred felt something on her lips, before realizing that the King had kissed her.

Her eyes widened, disbelieving; as the King completed the invasion of her space by wrapping her curvaceous body around her own, and rooting her in place. At first, her lips stiffened, resisting the foreign feel of Artoria's mouth. Then the sweet scent of the King's body made her relax, which gave the latter the impetus to thrust her tongue through.

"Hmrr..!" Caught off-guard, Mordred could do nothing but struggle as the King began methodically wrapping her slimy tongue around her own. Artoria licked and sucked, took and gave; and all Mordred felt was a floating listlessness as she fought to keep track of her own breathing. Then, with a loud smack, the King finally disengaged, leaving Mordred a dazed, open-mouthed, and frightened wreck.

The King purred. "Mmm.. You're an excellent one. Yes... good... Very good..."

"I'm... good...?" Mordred asked, gasping, as the King launched an exploration of her mouth over the rest of her body, starting from her chin, then layering kisses all down her neck, then on her bared collarbone; the King then expertly unclasped the bands on her chest; and when Mordred was unburdened of her clothes, the King took to slurping over the curve of her shoulder; then raised her arm to kiss her pit before travelling down to flick her tongue over her nipple. All this, combined, made Mordred gasp and whine-unable to muster a defense, she remained utterly bewildered, floating on the edge of something warm and scary and pleasurable; as Artoria steadily stripped her body and claimed every revealed inch of skin with her mouth.

"Ffft... Aahhh... Delicious..." the King said in a small growl. Mordred watched, through lidded eyes, her cheeks flushed, as the King beheld her handiwork: Mordred's upper body now completely naked, dripping wet and shiny with royal spit. Mordred shuddered, as much from the sudden chill as the feel of being completely exposed to her King.

"Now then-here is what you've been waiting for." The King pushed Mordred down by the shoulder until she knelt, as if she were waiting for an accolade. "I know you've been quite excited to claim this for your own." A rustling of clothes followed, then Artoria widened the opening around her crotch-to reveal the most unbelievable thing Mordred had ever seen.

A pillar of flesh rose from within, revealed in all its erect glory. Though not used to such things, Mordred easily identified it for what it was-and also knew that it should not be possible for such a thing to be.

"Is it really that unbelievable? After all, I am your step- _father_ , Mordred. Behold, the sword you've sought: Excalibur." A small smirk came to Artoria as she displayed her girl-dick proudly.

"Th-there's a mistake. I wasn't actually... haaahh..." She gasped in shock as the thick, veiny thing was laid against her shoulder, resting there on her skin like an iron hot poker. The smell of it was so strong and overpowering that it almost felt like she were going drunk.

Artoria slid the cock up over her hair, then rested it on her other shoulder, closer to her cheek. "You're cute," Artoria declared. She slowly circled the tip of her cock against Mordred's face, making her whine in confusion. Artoria's penis paused near her nose-causing Mordred to inhale lungfuls of her stepfather's musk-and said, "Well, here it is. Please take care."

Hesitantly, she licked the glans with the tip of her tongue. She felt a wave of shame course through her when she saw the dark amusement clear in her stepfather's eyes. Though she did glow with a little pride when Artoria caressed her hair, giving her the twisted impetus to grow bolder. She licked beneath her shaft, going from root to tip, and steadily found her shame disappearing, giving way to a perverted sort of worship. It seemed like instinct, somehow, for her to worship a "weapon" of such considerable length and girth. She grew a bit more bold and playful, and she engulfed up to half of her stepfather's shaft into her mouth, just up to the point of her throat. She looked up at Artoria.

"Hrm... Very nice. I see you're quite new to it. But I don't mind. Now let's do something better."

Mouth still full of girlcock, she raised her brow and said, "Eh?"

With one determined thrust, Artoria plunged her shaft deep and hard into Mordred's mouth. Uttering a wail of surprise deep within her throat, Mordred could do nothing but choke on the tremendous size, which now endeavored to brutalize her throat through its sheer length. Breathing hard, drool dribbling down her chin, she looked up through teary eyes at her stepfather, who patted her head. Then, she withdrew her length, just enough for the tip to knock against the back of Mordred's front teeth, before she thrust it back inside, bringing pain and a fresh wave of tears.

The King seemed to know how to wield this mighty "weapon" as she did any other. She ignored near all of Mordred's muffled squeals and only seemed to draw even greater pleasure from her discomfort. She did her best to keep her jaw slack and loose, fearing what the King would do or say if she snagged her weapon with her teeth.

Mordred saw that the King drew pleasure from face-fucking her, glimpsing the first sign of true emotion. Artoria's face was raised to the ceiling, and she bit her mouth as pleased hums sounded in her throat. Her great boobs heaved and wobbled with every thrust of her hips.

Then, she felt her cock twitch in her mouth. Even more, it seemed to grow in size, making her cheeks bulge. A hand now gripped the back of Mordred's head tight as Artoria uttered a pleased hiss. A moment later, something hot and burning burst through the back of her mouth. Mordred could only whine as the liquid began to shoot in great big gobs down her throat, travelling all the way down to settle warmly in her stomach.

"Good... yes..." Artoria said, caressing Mordred's sweat-ridden face, comforting her as she planted her load deep within her.

After what seemed like eternity, she felt the King push her away roughly by the shoulder. Her shaft popped back out of her mouth, and made a sound like a cork being unstopped. It swung free, slapping her slightly on the cheek, before something white and hot erupted from the tip, making Mordred gasp in surprise, even as semen dribbled down her chin. The sticky substance that had been shot through her throat now splattered all over her body, rapidly painting her skin in milky white. When it finally ended, she literally bathed in her stepfather's stinky spunk, which relentlessly rained down from her tower of flesh.

"...I seem to have made a mess, I am sorry."

Using a nearby cloth, Artoria wiped the drying, cooling mess of juices from Mordred's body. Dazed, she could only wonder at the abrupt change in her stepfather's demeanor: one moment she was rough and forceful, and in the next, caring and gentle. She softly peeled away the rest of her soggy, stinking clothes, laid them aside. Now Mordred was thoroughly exposed, her slender, athletic build paling in comparison to the visage of beauty exemplified by Artoria.

Artoria remarked, "That will smell. I have oils that will help with it. Come to the bed and lie yourself down."

Mordred nodded dumbly, too out of it to even start worrying about dirtying the King's own royal bed. She laid down on the soft mattress as ordered, while Artoria rummaged among a table of bottles and vials.

"Here we are. No, be at peace. Just lay there as you are."

"But-"

"Do not argue," Artoria said firmly, placing a hand between her shoulder-blades to keep her from rising. Mordred sighed when she gave her a faint, feathery caress with her warm, soothing palm. It felt oddly nice and comfortable, a distinct contrast from the uncertainty and pain from just a few moments before. When Artoria began to spread the oil over her skin, it felt warm and produced a fragrant smell. "There now. It is not enough to be a full apology to you, my dear son, but it is a start, is it not?"

Mordred felt herself melt into the pleasure of her stepfather's fingers. Her expert touches and squeezes made her gasp and squeal. She felt her stepfather increase the pressure gradually, kneading her lubricated skin with increasing mastery. A vibrating thrill shot through her when her hands ranged lower, now palming and massaging her thighs.

"You seem to like this," Artoria observed.

"Haaah... yes..."

"Good."

"Ah!" She squirmed, moving her hips from side to side as the pleasure made her crotch feel a funny sort of tingling. Then, Artoria's hands landed on her buttcheeks, making her freeze. It felt kind of embarrassing to feel the King to knead her butt-cheeks like dough. Then she felt her hands spread them apart, and it got even more embarrassing!

"Do not move," Artoria said quickly as she tried to stand.  _I fucking knew there was something fishy about this! This ain't a normal massage!_  Mordred shuddered and hissed as the fingers now explored somewhere definitely lewd-one hand caressing over her exposed slit, while the other teased over the entrance of her anus.

"No, wait, that is filthy-"

"Hush."

Mordred hated how pathetic her whimpering sounded as Artoria raised her hips for greater coverage. It felt humiliating to be on display to her stepfather like this. And yet, just as she had been when she'd rammed her cock down her throat, Artoria displayed a merciless cunning as she methodically stripped Mordred of all remaining dignity. Every flick of her aroused cunt sent lightning shocks up to her head; at the same time, a finger eased its way into her pucker, making her feel like she were hanging from a dozen threads. Through Artoria's method, the slow and steady invasion of Mordred's anal walls were accompanied by the thrill of pleasure engineered through her pussy's arousal.

Artoria's finger wiggled as it dug inside her rectum. Inch by inch she advanced, and when she bottomed out, Mordred could only gasp out her discomfort-as the particularly wicked way Artoria flicked her clit sent shockwaves of pleasure to combat it. Then, she began to twist her finger in and out of her ass, and Mordred's body went crazy. She rocked and seized like a captured fish, all parts of her rational mind lost to the heady sensation of pleasure. Hot, fresh juices ran freely down her thighs to stain the royal bed.

Mordred had felt it building up to a glorious, shuddering peak, and yet before she could reach that point, Artoria stopped: removing her finger from her ass, her sphincter making a soft pop before closing, while straight out stopping her service of her cunt. Mordred was left grunting wildly, her expression needy, though it was hidden when she buried her face into the bed.

"Let us see if you are ready."

She felt Artoria move into position behind her. She felt her hips being raised, her legs spread as far as it could, while the King's thicker thighs supported her own. Then she could feel all the enormous strength of the royal "weapon" against her butt, and she immediately knew the purpose of this new offensive. The King speared her cock in between her asscheeks, making both sides squeeze around her shaft. Then she heard the King unload even more of the strange oily substance on lower back, before scooping it up to lather all over her shaft. Lastly, she felt the King's glans line up just outside her pucker.

"Oi, oi, now wait just a goddamned-" Whatever Mordred was about to say about this was drowned out by the strong, meaty sound of an ass being impaled, and of her screaming out for all the world to hear. Her asshole constricted like a vice around the royal intruder, and she felt it as the last bit of resistance she had in her. But it was a losing battle; and she could feel its stinging rip through the rings of her anus to reach the core of her ass. Then Artoria bent over her body, teasing her back with her sagging teats, before she slowly pushed her penis backward, and then thrusted it back inside again.

"Ohhh, haaa fuck it... haaah fuck, fuck, fuck... kkahh... haaah!"

From her position fucking the so-called Knight of Treachery in the ass, Artoria wound her arms down and around her belly, until her fingers caught her arousal. As Artoria began to scoop miles of her inner asshole with every thrust of her dick, she caught and played with the erect hood of her clit, causing Mordred's back to arc from sheer pleasure.

She quickly began to build towards her peak yet again, and this time there seemed to be nothing to stop it. With Artoria's dick firmly embedded in her anal hole, and her fingers restlessly playing over her cunt, it didn't take long for Mordred's legs to give out, as a great, heaving spasm crashed through her. Her throat rambled nonsense words as the orgasm shook every inch of her body.

Then she felt the cock inside her anus twitch and tremble. The second glorious orgasm to come from the King's royal "weapon" jetted out, spraying thick ropes of searing cum deep inside her twitching bowels. Heat slowly began to build from deep within her gut as her ass was fully pumped with the King's seed, though in her condition she could make no further comment on it but the hoarse groans that came from her throat.

When clarity returned to her, she found that the King was now kissing all over the valley between her shoulderblades. Noticing her stir, Artoria said, "That was very well done, my child. Very good. You've pleased me."

"Haah... ahhh... haaah... Thank you... father..." She made to move, but found that every thing from her hips down seemed sluggish and painful to move. Then she found that father was still firmly entrenched within her, the royal cock now a plug that contained the flood of sticky warmth within her bowels. She peered over her shoulder at her stepfather, who only smiled mysteriously in reply.

"Did I not tell you that I would give this weapon to you-in all its entirety?"

Mordred's eyes widened as Artoria pressed her body down over her, fully overshadowing her smaller frame with her own. She gasped as she felt the twisted pleasure of her stepfather's massive girth withdrawing from her ass, before they drove back in. Artoria took Mordred's hands in her own, ruthlessly keeping her in place, while restarting the rhythm that literally pushed her whole body forward, then backward, then forward once again.

Mordred wheezed and sighed, her eyes rolling up to the back of her head as her once tight, virginal ass was plundered fully by the King's royal "weapon". For that long night Mordred fulfilled her role as the receptacle for Artoria's lusts, until gallons of semen settled in her belly. She could well swear that even when Artoria concluded that it was over, her dick was still rock hard and ready to go. A mighty weapon indeed.

Mordred would note her asshole would never be the same; conversely the relationship with her stepfather would also change-for the better, or so she hoped.

 

 

**Author's Note:**

> An anonymous commission, thank you.
> 
> If you'd like a story commissioned, simply message me on "The Ruff Pusher" on fanfiction.net or on my tumblr at theruffpusherdottumblrdotcom.


End file.
